<template>
  <view class="u-wrap">
    <view class="u-search-box">
      <view class="u-search-inner" @tap="$Router.push({ path: '/pages/common/good/list', query: { search: '' } })">
        <u-icon name="search" color="#909399" :size="28"></u-icon>
        <text class="u-search-text">搜索</text>
      </view>
    </view>
    <view class="u-menu-wrap">
      <scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop">
        <view v-for="(item,index) in categoryList" :key="index" class="u-tab-item" :class="[current === index ? 'u-tab-item-active' : '']"
              @tap.stop="swichMenu(index)">
          <text class="u-line-1">{{item.name}}</text>
        </view>
      </scroll-view>
      <block v-for="(item,index) in categoryList" :key="index">
        <scroll-view scroll-y class="right-box" v-if="current===index">
          <view class="page-view">
            <view class="class-item">
              <view class="item-title">
                <text>{{item.name}}</text>
              </view>
              <view class="item-container">
                <view class="thumb-box" v-for="(itema, indexa) in item.children" :key="indexa" @tap="$Router.push({ path: '/pages/common/good/list', query: { id: itema.id } })">
                  <image class="item-menu-image" :src="itema.img" mode=""></image>
                  <view class="item-menu-name">{{itema.name}}</view>
                </view>
              </view>
            </view>
          </view>
        </scroll-view>
      </block>
    </view>
  </view>
</template>

<script>
import {handleTree} from "@/faasmall/utils/faasmall"
import {getCategoryList} from "@/faasmall/api/category";
export default {
  data() {
    return {
      categoryList: [],
      scrollTop: 0, //tab标题的滚动条位置
      current: 0, // 预设当前项的值
      menuHeight: 0, // 左边菜单的高度
      menuItemHeight: 0, // 左边菜单item的高度
    }
  },
  onLoad() {
    this.getAllCategory();
  },
  methods: {
    getAllCategory(){
      getCategoryList().then((response)=>{
        this.categoryList = handleTree(response.data, "id");
        console.log(this.categoryList)
      }).catch(error=>{
        console.error(error)
      })
    },
    // 点击左边的栏目切换
    async swichMenu(index) {
      if(index == this.current) return ;
      this.current = index;
      // 如果为0，意味着尚未初始化
      if(this.menuHeight == 0 || this.menuItemHeight == 0) {
        await this.getElRect('menu-scroll-view', 'menuHeight');
        await this.getElRect('u-tab-item', 'menuItemHeight');
      }
      // 将菜单菜单活动item垂直居中
      this.scrollTop = index * this.menuItemHeight + this.menuItemHeight / 2 - this.menuHeight / 2;
    },
    // 获取一个目标元素的高度
    getElRect(elClass, dataVal) {
      new Promise((resolve, reject) => {
        const query = uni.createSelectorQuery().in(this);
        query.select('.' + elClass).fields({size: true},res => {
          // 如果节点尚未生成，res值为null，循环调用执行
          if(!res) {
            setTimeout(() => {
              this.getElRect(elClass);
            }, 10);
            return ;
          }
          this[dataVal] = res.height;
        }).exec();
      })
    }
  }
}
</script>

<style lang="scss" scoped>
.u-wrap {
  height: calc(100vh);
  /* #ifdef H5 */
  height: calc(100vh - var(--window-top));
  /* #endif */
  display: flex;
  flex-direction: column;
}

.u-search-box {
  padding: 18rpx 30rpx;
}

.u-menu-wrap {
  flex: 1;
  display: flex;
  overflow: hidden;
}

.u-search-inner {
  background-color: rgb(234, 234, 234);
  border-radius: 100rpx;
  display: flex;
  align-items: center;
  padding: 10rpx 16rpx;
}

.u-search-text {
  font-size: 26rpx;
  color: $u-tips-color;
  margin-left: 10rpx;
}

.u-tab-view {
  width: 200rpx;
  height: 100%;
}

.u-tab-item {
  height: 110rpx;
  background: #f6f6f6;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26rpx;
  color: #444;
  font-weight: 400;
  line-height: 1;
}

.u-tab-item-active {
  position: relative;
  color: #000;
  font-size: 30rpx;
  font-weight: 600;
  background: #fff;
}

.u-tab-item-active::before {
  content: "";
  position: absolute;
  border-left: 4px solid $mszf-theme-color;
  height: 32rpx;
  left: 0;
  top: 39rpx;
}

.u-tab-view {
  height: 100%;
}

.right-box {
  background-color: rgb(250, 250, 250);
}

.page-view {
  padding: 16rpx;
}

.class-item {
  margin-bottom: 30rpx;
  background-color: #fff;
  padding: 16rpx;
  border-radius: 8rpx;
}

.item-title {
  font-size: 26rpx;
  color: $u-main-color;
  font-weight: bold;
}

.item-menu-name {
  font-weight: normal;
  font-size: 24rpx;
  color: $u-main-color;
}

.item-container {
  display: flex;
  flex-wrap: wrap;
}

.thumb-box {
  width: 33.333333%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  margin-top: 20rpx;
}

.item-menu-image {
  width: 120rpx;
  height: 120rpx;
}
</style>
